Addendum/Appendix
An addendum (or appendix) is a supplement to a document, typically consisting of additional information that clarifies or updates the original document. If you’re creating a document and you realize that you’ve left out some important information, you can add that information as an addendum. An addendum can also be used to provide updated information, such as new data or changed procedures. Addenda are usually added to the end of the document, although they can be placed anywhere that makes sense. If there is more than one addendum, they are usually labelled as Appendix A, Appendix B, and so on. The word “addendum” is singular; the plural form is “addendums” or “addenda.”